Abstract: An structure for electrically isolating a semiconductor device is formed by implanting dopant into a semiconductor substrate that does not include an epitaxial layer. Following the implant the structure is exposed to a very limited thermal budget so that dopant does not diffuse significantly. As a result, the dimensions of the isolation structure are limited and defined, thereby allowing a higher packing density than obtainable using conventional processes which include the growth of an epitaxial layer and diffusion of the dopants. In one group of embodiments, the isolation structure includes a deep layer and a sidewall which together form a cup-shaped structure surrounding an enclosed region in which the isolated semiconductor device may be formed. The sidewalls may be formed by a series of pulsed implants at different energies, thereby creating a stack of overlapping implanted regions.

Abstract: An structure for electrically isolating a semiconductor device is formed by implanting dopant into a semiconductor substrate that does not include an epitaxial layer. Following the implant the structure is exposed to a very limited thermal budget so that dopant does not diffuse significantly. As a result, the dimensions of the isolation structure are limited and defined, thereby allowing a higher packing density than obtainable using conventional processes which include the growth of an epitaxial layer and diffusion of the dopants. In one group of embodiments, the isolation structure includes a deep layer and a sidewall which together form a cup-shaped structure surrounding an enclosed region in which the isolated semiconductor device may be formed. The sidewalls may be formed by a series of pulsed implants at different energies, thereby creating a stack of overlapping implanted regions.

Abstract: A family of semiconductor devices is formed in a substrate that contains no epitaxial layer. In one embodiment the family includes a 5V CMOS pair, a 12V CMOS pair, a 5V NPN, a 5V PNP, several forms of a lateral trench MOSFET, and a 30V lateral N-channel DMOS. Each of the devices is extremely compact, both laterally and vertically, and can be fully isolated from all other devices in the substrate.

Abstract: A family of semiconductor devices is formed in a substrate that contains no epitaxial layer. In one embodiment the family includes a 5V CMOS pair, a 12V CMOS pair, a 5V NPN, a 5V PNP, several forms of a lateral trench MOSFET, and a 30V lateral N-channel DMOS. Each of the devices is extremely compact, both laterally and vertically, and can be fully isolated from all other devices in the substrate.

Abstract: The a trench semiconductor device such as a power MOSFET the high electric field at the corner of the trench is diminished by increasing the thickness of the gate oxide layer at the bottom of the trench. Several processes for manufacturing such devices are described. In one group of processes a directional deposition of silicon oxide is performed after the trench has been etched, yielding a thick oxide layer at the bottom of the trench. Any oxide which deposits on the walls of the trench is removed before a thin gate oxide layer is grown on the walls. The trench is then filled with polysilicon in or more stages. In a variation of the process a small amount of photoresist is deposited on the oxide at the bottom of the trench before the walls of the trench are etched. Alternatively, polysilicon can be deposited in the trench and etched back until only a portion remains at the bottom of the trench. The polysilicon is then oxidized and the trench is refilled with polysilicon.

Abstract: A semiconductor package contains a plurality of sheet metal leads that are attached to one or more terminals on a top side of a semiconductor die. A heat sink is attached to a terminal on a bottom side of the die. Each of the leads extends across the die and beyond opposite edges of the die and is symmetrical about an axis of the die. At the locations where the leads pass over the edges of the die notches are formed on the sides of the leads which face the die, thereby assuring that there is no contact between the leads and the peripheral portion of the top surface of the die. Particularly in power MOSFETs the peripheral portion of the top surface normally contains an equipotential ring which is directly connected to the backside (drain) of the MOSFET, and hence a short between the leads on the top of the die and the equipotential ring would destroy the device. The result is a package that is extremely rugged and that is symmetrical about the axis of the die.

Abstract: A “chained implant” technique forms a body region in a trench gated transistor. In one embodiment, a succession of “chained” implants can be performed at the same dose but different energies. In other embodiments different doses and energies can be used, and particularly, more than one dose can be used in a single device. This process produces a uniform body doping concentration and a steeper concentration gradient (at the body-drain junction), with a higher total body charge for a given threshold voltage, thereby reducing the vulnerability of the device to punchthrough breakdown. Additionally, the source-body junction does not, to a first order, affect the threshold voltage of the device, as it does in DMOS devices formed with conventional diffused body processes.

Abstract: A trench-gated MOSFET formed using a super self aligned (SSA) process employs an insulating layer such as a glass layer and a contact mask to define contact openings for electrical connections to source regions of the MOSFET. Use a contact mask and an intervening glass in otherwise self-aligned process reduces the coupling capacitance between source metal and the top of the embedded trench gate. A metal layer deposited to make electrical contact to source regions can be planarized, for example, ground flat using chemical-mechanical polishing to provide a flat surface to avoid formation of conductive traces that extend over the steps that the glass layer forms.

Abstract: Power MOSFETs and fabrication processes for power MOSFETs use a continuous conductive gate structure within trenches to avoid problems arising from device topology caused when a gate bus extends above a substrate surface. The conductive gate structure forms gates in device trenches in an active device region and forms a gate bus in a gate bus trench. The gate bus trench that connects to the device trenches can be wide to facilitate forming a gate contact to the gate bus, while the device trenches can be narrow to maximize device density. CMP process can be used to planarize the conductive gate structure and/or overlying insulating layers. The processes are compatible with processes forming self-aligned or conventional contacts in the active device region.

Abstract: A super-self-aligned (SSA) structure and manufacturing process uses a single photomasking layer to define critical features and dimensions of a trench-gated vertical power DMOSFET. The single critical mask determines the trench surface dimension, the silicon source-body mesa width between trenches, and the dimensions and location of the silicon mesa contact. The contact is self-aligned to the trench, eliminating the limitation imposed by contact-to-trench mask alignment in conventional trench DMOS devices needed to avoid process-induced gate-to-source shorts. Oxide step height above the silicon surface is also reduced avoiding metal step coverage problems. Poly gate bus step height is also reduced. Other features described include polysilicon diode formation, controlling the location of drain-body diode breakdown, reducing gate-to-drain overlap capacitance, and utilizing low-thermal budget processing techniques.

Abstract: A semiconductor die has a bonding pad for a MOSFET such as a power MOSFET and a separate bonding pad for ESD protection circuitry. Connecting the bonding pads together makes the ESD protection circuitry functional to protect the MOSFET. Before connecting the bonding pads together, the ESD protection circuitry and/or the MOSFET can be separately tested. A voltage higher than functioning ESD protection circuitry would permit can be used when testing the MOSFET. A packaging process such as wire bonding or attaching the die to a substrate in a flip-chip package can connect the bonding pads after testing.

Abstract: A super-self-aligned (SSA) structure and manufacturing process uses a single photomasking layer to define critical features and dimensions of a trench-gated vertical power DMOSFET. The single critical mask determines the trench surface dimension, the silicon source-body mesa width between trenches, and the dimensions and location of the silicon mesa contact. The contact is self-aligned to the trench, eliminating the limitation imposed by contact-to-trench mask alignment in conventional trench DMOS devices needed to avoid process-induced gate-to-source shorts. Oxide step height above the silicon surface is also reduced avoiding metal step coverage problems. Poly gate bus step height is also reduced. Other features described include polysilicon diode formation, controlling the location of drain-body diode breakdown, reducing gate-to-drain overlap capacitance, and utilizing low-thermal budget processing techniques.

Abstract: Circuits and methods to trim analog integrated circuits, such as five-pin linear voltage regulators, after packaging are disclosed. In an exemplary embodiment, a test mode input circuit determines establishment of a test mode operation of the analog integrated circuit. A register control circuit generates a data signal and a plurality of control signals. A register circuit, including an input shift register and a plurality of storage devices, receives the data signal and the control signals, programs the storage devices as directed, and generates a plurality of trim control signals based on the states of the storage devices. A trim control circuit applies the trim control signals to modify a normal operation of the packaged analog integrated circuit. The analog integrated circuit and the circuits to trim the analog integrated circuit may be included in a same package.

Abstract: A super-self-aligned (SSA) structure and manufacturing process uses a single photomasking layer to define critical features and dimensions of a trench-gated vertical power DMOSFET. The single critical mask determines the trench surface dimension, the silicon source-body mesa width between trenches, and the dimensions and location of the silicon mesa contact. The contact is self-aligned to the trench, eliminating the limitation imposed by contact-to-trench mask alignment in conventional trench DMOS devices needed to avoid process-induced gate-to-source shorts. Oxide step height above the silicon surface is also reduced avoiding metal step coverage problems. Poly gate bus step height is also reduced. Other features described include polysilicon diode formation, controlling the location of drain-body diode breakdown, reducing gate-to-drain overlap capacitance, and utilizing low-thermal budget processing techniques.

Abstract: Circuits and methods to turn-on a power MOSFET switch while limiting rush current delivered to a load are disclosed. In an exemplary embodiment, a sense circuit senses when the power MOSFET is enhanced by a first level and a second level. A control circuit controls application of three drive forces to the gate of the power MOSFET in response to the sense circuit. The first drive force adjusts the voltage applied to the gate at a first rate. The second drive force adjusts the voltage applied to the gate at a second rate less than the first rate. The third drive force adjusts the voltage applied to the gate at a third rate greater than the second rate. The circuit utilizes most of the allotted turn-on time to linearly control the power MOSFET enhancement, providing optimal slew rate control and limiting the rush current delivered to the load.

Abstract: A super-self-aligned (SSA) structure and manufacturing process uses a single photomasking layer to define critical features and dimensions of a trench-gated vertical power DMOSFET. The single critical mask determines the trench surface dimension, the silicon source-body mesa width between trenches, and the dimensions and location of the silicon mesa contact. The contact is self-aligned to the trench, eliminating the limitation imposed by contact-to-trench mask alignment in conventional trench DMOS devices needed to avoid process-induced gate-to-source shorts. Oxide step height above the silicon surface is also reduced avoiding metal step coverage problems. Poly gate bus step height is also reduced. Other features described include polysilicon diode formation, controlling the location of drain-body diode breakdown, reducing gate-to-drain overlap capacitance, and utilizing low-thermal budget processing techniques.

Abstract: A current-limited switch contains a pilot circuit in parallel with a power MOSFET and a reference circuit containing a series of parallel circuits, each of which contains a current mirror MOSFET in parallel with a resistor. A current mirror compensation circuit contains circuitry which shorts out the parallel circuits in sequence as the current through the power MOSFET increases, thereby limiting the size of the current through the power MOSFET. In a preferred embodiment a body control circuit is connected to the power MOSFET to ensure that the body diode in the power MOSFET does not become forward-biased and thereby permit a flow of current through the power MOSFET even when it is turned off.

Abstract: A semiconductor package contains a plurality of sheet metal leads that are attached to one or more terminals on a top side of a semiconductor die. A heat sink is attached to a terminal on a bottom side of the die. Each of the leads extends across the die and beyond opposite edges of the die and is symmetrical about an axis of the die. At the locations where the leads pass over the edges of the die notches are formed on the sides of the leads which face the die, thereby assuring that there is no contact between the leads and the peripheral portion of the top surface of the die. Particularly in power MOSFETs the peripheral portion of the top surface normally contains an equipotential ring which is directly connected to the backside (drain) of the MOSFET, and hence a short between the leads on the top of the die and the equipotential ring would destroy the device. The result is a package that is extremely rugged and that is symmetrical about the axis of the die.

Abstract: A novel super-self-aligned (SSA) structure and manufacturing process uses a single photomasking layer to define critical features and dimensions of a trench-gated vertical power DMOSFET. The single critical mask determines the trench surface dimension, the silicon source-body mesa width between trenches, and the dimensions and location of the silicon mesa contact. The contact is self-aligned to the trench, eliminating the limitation imposed by contact-to-trench mask alignment in conventional trench DMOS devices needed to avoid-process-induced gate-to-source shorts. Oxide step height above the silicon surface is also reduced avoiding metal step coverage problems. Poly gate bus step height is also reduced. Other features described include polysilicon diode formation, controlling the location of drain-body diode breakdown, reducing gate-to-drain overlap capacitance, and utilizing low-thermal budget processing techniques.

Abstract: A current-limited switch contains a pilot circuit in parallel with a power MOSFET and a reference circuit containing a series of parallel circuits, each of which contains a current mirror MOSFET in parallel with a resistor. A current mirror compensation circuit contains circuitry which shorts out the parallel circuits in sequence as the current through the power MOSFET increases, thereby limiting the size of the current through the power MOSFET. In a preferred embodiment a body control circuit is connected to the power MOSFET to ensure that the body diode in the power MOSFET does not become forward-biased and thereby permit a flow of current through the power MOSFET even when it is turned off.